HFBR-59L1AGEZ Datasheet, PDF (3/13 Pages) AVAGO TECHNOLOGIES LIMITED – 1.25 GBd Ethernet and 1.0625 GBd Fibre Channel 850 nm SFF Low Voltage (3.3 V) Optical Transceiver

Transmitter Section
The transmitter section includes an 850 nm VCSEL (Verti-
cal Cavity Surface Emitting Laser) light source and a trans-
mitter driver circuit. The driver circuit maintains a constant
optical power level provided that the data pattern is valid
8B/10B code. Connection to the transmitter is provided
via an LC optical connector.
TX Disable
The HFBR-59L1AL accepts a LVTTL transmit disable con-
trol signal input which shuts down the transmitter. A high
signal implements this function while a low signal allows
normal laser operation. In the event of a fault (e.g., eye
safety circuit activated), cycling this control signal resets
the module. The TX Disable control should be actuated
upon initialization of the module. See Figure 5 for product
timing diagrams.
Eye Safety Circuit
For an optical transmitter device to be eye-safe in the
event of a single fault failure, the transmitter will either
maintain normal, eye-safe operation or be disabled. In the
event of an eye safety fault, the VCSEL will be disabled.
Receiver Section
Connection to the receiver is provided via an LC optical
connector. The receiver circuit also includes a Signal De-
tect (SD) circuit which provides an open collector logic
low output in the absence of a usable input optical signal
level.
Signal Detect
The Signal Detect (SD) output indicates if the optical input
signal to the receiver does not meet the minimum detect-
able level for Fibre Channel compliant signals. When SD is
low it indicates loss of signal. When SD is high it indicates
normal operation. The Signal Detect thresholds are set to
indicate a definite optical fault has occurred (e.g., discon-
nected or broken fiber connection to receiver, failed trans-
mitter).
Functional Data I/O
Avago’s HFBR-59L1AL fiberoptic transceiver is designed to
accept industry standard differential signals. In order to re-
duce the number of passive components required on the
customer’s board, Avago has included the functionality
of the transmitter bias resistors and coupling capacitors
within the fiber optic module. The transceiver is compat-
ible with an “ac-coupled” configuration and is internally
terminated. Figure 1 depicts the functional diagram of the
HFBR-59L1AL. Caution should be taken to account for the
proper interconnection between the supporting Physical
Layer integrated circuits and the HFBR-59L1AL. Figure 3
illustrates the recommended interface circuit.
Reference Designs
Figure 3 depicts a typical application configuration, while
Figure 4 depicts the multisourced power supply filter cir-
cuit design. Regulatory Compliance See Table 1 for trans-
ceiver Regulatory Compliance performance. The overall
equipment design will determine the certification level.
The transceiver performance is offered as a figure of merit
to assist the designer.
Electrostatic Discharge (ESD)
There are two conditions in which immunity to ESD dam-
age is important. Table 1 documents our immunity to
both of these conditions. The first condition is during han-
dling of the transceiver prior to attachment to the PCB.
To protect the transceiver, it is important to use normal
ESD handling precautions. These precautions include us-
ing grounded wrist straps, work benches, and floor mats
in ESD controlled areas. The ESD sensitivity of the HFBR-
59L1AL is compatible with typical industry production
environments. The second condition is static discharges
to the exterior of the host equipment chassis after instal-
lation. To the extent that the duplex LC optical interface
is exposed to the outside of the host equipment chassis,
it may be subject to system-level ESD requirements. The
ESD performance of the HFBR- 59L1AL exceeds typical in-
dustry standards.
Immunity
Equipment hosting the HFBR- 59L1AL modules will be
subjected to radio-frequency electromagnetic fields in
some environments. The transceivers have good immu-
nity to such fields due to their shielded design.
Electromagnetic Interference (EMI)
Most equipment designs utilizing these high-speed
transceivers from Avago Technologies will be required to
meet the requirements of FCC in the United States, CEN-
ELEC EN55022 (CISPR 22) in Europe and VCCI in Japan. The
metal housing and shielded design of the HFBR-59L1AL
minimize the EMI challenge facing the host equipment
designer.
These transceivers provide superior EMI performance.
This greatly assists the designer in the management of the
overall system EMI performance.
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